Comparison of Observations of Sea Surface Temperatures at Ocean Station P and NOAA Buoy Stations and Those Made by Merchant Ships Traveling in Their Vicinities, in the Northeast Pacific Ocean

Abstract

An analysis of the 6 h observations of sea surface temperatures made at Station P and the eight NOAA buoy stations in the northeast Pacific Ocean indicates that the buoys appear to be providing data that are as reliable as from Station P. On the basis of the total number of observations available for each station, the mean standard deviation associated with the 3½-day average temperatures varied from ±0.1 to ±0.2°C. There are indications that the summer values of the standard deviation are somewhat higher than during the remaining months. This is attributed to the effect of diurnal heating and cooling of the surface waters. The larger values noted for autumn and winter are attributed to the effect of the rapid rate of cooling of surface waters and/or to the influence of water mass movements. A comparison has been made between the temperatures obtained at the time-series stations and by merchant ships in their vicinities. The results show that the ships' temperatures are 0.2 ± 1.5°C greater than those of the time-series stations. The quality of the ships' temperatures is not as good as it ought to be and efforts should be directed to improving it. For some locations there is some evidence that the horizontal temperature gradient present in the localities might be affecting the temperature differences between the time-series stations and ships' observations. An improvement of the quality of the ships' data by reducing the standard deviation from ¼ to ½ of the presently determined values should be sufficient to determine this at the 95% confidence level.